Umbrella and parasol are widely used articles to protect people from getting wet in rainy day or suffering sunburn in sunny day.
In the earlier time, an umbrella rod and frame are made from tough and elastic bamboo. Strong cotton threads are wound on the frame, and paper impregnated with a selected oil is used as an umbrella panel. The impregnated panel can only fend off small rain. It is easily destroyed by strong wind or heavy rain. Hence it may look nicely, but has little practical value. Nowadays, a wide variety of umbrellas are available, such as folding umbrellas, parasols, and the like. They are not only designed with aesthetic appealing, also are tough and reliable. The folding umbrella is light and compact, and easy to carry. But it is easily damaged but strong wind and gale. The parasol generally is a special type of umbrella made in a larger size. The following mainly focuses on the design and application of the parasol.
Refer to FIG. 1 for a conventional large size parasol. It has a runner 12 movable on a vertical rod 11 to an action position and a departing position. The runner 12 serves as the pivot center of the frame 13. When the runner 12 is moved to the action position, the frame 13 will be driven to extend a panel 14. An anchor element 15 is provided on the vertical rod 11 at the action position. The anchor element 15 is a movable jutting member to keep the runner 12 at the action position and maintain the panel 14 at the extended condition. Basically it adopts the design of the folding umbrella without much difference. The main difference is the size and material. As the conventional large parasol is coupled through the runner 12 and anchor element 15, and there is no other means to firmly hold the runner 12, it is not very steady or reliable when in use. The anchor element 15 usually is a thin metal latch. When users try to extend the parasol, they have to grasp the runner 12 with one hand and hold the vertical rod 11 with another hand to move the runner in the axial direction to extend or collapse the panel 14. Moving the runner 12 tends to injure user's hands. Moreover, the anchor element 15 has a very small area to receive force. Thus folding the parasol is quite difficult and user's hands are easily hurt.